The invention relates to the purification of effluent gases containing sulfuric acid fumes.
Collection and disposal of sulfuric acid fumes is a problem in many industrial processes, such as pickling, metal plating, plastic plating, aluminum anodizing and battery forming or charging. During the production of battery plates, for example, sulfuric acid is employed in a tank at around 200.degree. F. Hot fumes escape and are generally pulled by vent fans normally mounted on the roof. The exit gases are then sent to a water scrubber such as the TRI-MER fan/separator sold by the Tri-Mer Corporation in Owosso, Mich. In this system the gases undergo primary laminar separation of heavy particles using high pressure, low volume water; secondary separation by hydrophobic tube pack; and tertiary separation by particle impaction and interception, at the end of which there is a 90.degree. directional air change to preclude blocking. Contaminated water is sent to liquid waste treatment or process reuse. Although water is very effective in removing acid from the vent stream, a large amount of water is used to trap all of the acid fumes, resulting in a very dilute effluent leaving the scrubber. Generally, caustic solution is used to neutralize the water. Thus most of the acid is totally lost and must be disposed of at considerable expense. The present invention provides a less expensive and more efficient reduction in the amount of sulfuric acid fumes discharged to the atmosphere without the use of scrubbing water and permits recycling of recovered acid.
One object of the present invention is to provide a reduction in the amount of sulfuric acid discharged to the atmosphere by as much as 99.0 to 99.99%.
Another object of the invention is to reduce the worker's exposure level to the sulfuric acid fumes.
A further object of the invention is to provide recycling of the sulfuric acid per se instead of a dilute solution.